ios - 无法更改 View 中绘制的圆的颜色

Question

我正在尝试更新我在 UIView 的子类中创建的圆圈的颜色通过在类中创建一个方法来更新颜色，如下所示，但颜色不会改变。

import UIKit

class badge: UIView {

    struct mine {
        static var p = UIBezierPath(ovalInRect: CGRectMake(0,0,100,100))

}

override func drawRect(rect: CGRect) {
    // Drawing code


    UIColor.blueColor().setFill()
    mine.p.fill()        

}


func colour(whatColour: String) {

    UIColor.redColor().setFill()
    mine.p.fill()
    self.setNeedsDisplay()

}
}

// The above is referenced in view controller with

@IBOutlet weak var myBadge: badge!

// change function colour is called with 

myBadge.colour()

// but the colour of the circle does not change (its still filled in blue)
}

我做错了什么？

Answer 1

更新:Swift 3(和 Swift 4)语法:

setNeedsDisplay 使 draw 再次运行，并将填充颜色设置回蓝色。尝试向您的 Badge View 添加一个属性来存储 desiredColour:

class Badge: UIView {

    var desiredColour: UIColor = .blue

    struct mine {
        static var p = UIBezierPath(ovalIn: CGRect(x: 0, y: 0, width: 100, height: 100))
    }

    override func draw(_ rect: CGRect) {
        // Drawing code

        desiredColour.setFill()
        mine.p.fill()
    }

    func colour() {
        desiredColour = .red
        self.setNeedsDisplay()
    }
}

---

如果您将didSet 添加到desiredColour，您可以让它为您调用setNeedsDisplay，然后您甚至不需要颜色功能。所以要使用它，您只需调用 myBadge.desiredColour = .red View 就会重绘!

class Badge: UIView {

    var desiredColour: UIColor = .blue {
        didSet {
            self.setNeedsDisplay()
        }
    }

    struct mine {
        static var p = UIBezierPath(ovalIn: CGRect(x: 0, y: 0, width: 100, height: 100))
    }

    override func draw(_ rect: CGRect) {
        // Drawing code

        desiredColour.setFill()
        mine.p.fill()
    }
}

---

它在 Swift Playground 中运行: